1. Field of the Invention
The present invention relates generally to medical devices and methods. In particular, the present invention relates to a reservoir and methods for its use for the collection of saliva with a reduction in bubbling and foaming.
A vacuum may be applied to an appliance or device held in a patient's oral cavity for a variety of purposes. For example, an appliance for treating obstructive sleep apnea (OSA) may utilize a device held in a patient's mouth where a vacuum is constantly drawn on the device in order to reposition portions of the patient's oral anatomy to reduce the likelihood of OSA. The device may be used for or in conjunction with drawing a patient's tongue and/or lower mandible forward in order to reduce OSA. Of particular interest to the present invention, the vacuum may be drawn in order to help draw the soft palate and/or rear portion of a patient's tongue away from the pharynx in order to maintain a clear breathing passage.
In all such devices which draw a partial negative pressure within the oral cavity, there is a likelihood that a flow of saliva will be created in tubes and other flow passages connected to the oral appliance to maintain the vacuum. In order to avoid fouling the equipment which produces the vacuum, a saliva collector may be provided in-line to remove and collect the saliva.
FIG. 1 is taken from FIG. 25 of co-pending, commonly owned U.S. Patent Publication No. 2012/0132216, the full disclosure of which is incorporated herein by reference. FIG. 1 illustrates a system 489 including an oral device 490, a vacuum pump 492, a saliva reservoir 494, and a pressure sensor 496. Oral device 490 further includes a pressure conduit 498 extending through bite structure 500 to the superior side of tongue constraint 502 where pressure conduit 498 has a distal opening 504. The pressure conduit 498 may alternatively comprise an inner lumen formed integrally within tongue constraint 502 or bite structure 500, and distal opening 504 could be positioned in any of various positions relative to bite structure 500 as may be desired to measure pressure within the oral cavity. A vacuum lumen 506 extends from the superior surface of tongue constraint 502 through bite structure 500 and both vacuum lumen 506 and pressure conduit 498 extend through lip seal 508. Vacuum lumen 506 is connected to a vacuum tube 510 which connects in an airtight manner to an input fitting 512 on saliva reservoir 494. Vacuum tube 510 has a vent hole 511 anterior to lip seal 508 so as to be outside the patient's oral cavity but positioned as close to oral device 490 as practicable while minimizing risk of obstruction by the patient's lips or other tissues. Alternatively vent hole 511 may be disposed in vacuum lumen 506 anterior to bite structure 500 or on the superior side of tongue constraint 502 so as to be located within the patient's oral cavity. When a negative pressure (partial vacuum) is applied through vacuum lumen 506 within the patient's oral cavity, saliva or other liquids which collect may be aspirated through vacuum lumen 506 and vacuum tube 510. While removing excess liquids from the oral cavity is desirable, the weight of the liquid within vacuum tube 510 may create a pressure offset in vacuum tube 510 which would then affect the negative pressure applied within the oral cavity. System 489 alleviates this problem by providing vent hole 511 in vacuum tube 510, allowing any aspirated liquids to flow to saliva reservoir 494 more quickly.
While effective, the saliva collection system described above can result in the mixing of air and saliva in the vacuum flow path which in turn will create bubbles and foam inside of the reservoir. In some cases, it is possible for the bubbles and foam to accumulate so that they reach the outlet fitting 516 connected to vacuum pump 492, as illustrated in FIG. 1. Even if the foaming does not reach that level, handling and/or accidental disturbance of the reservoir in such systems can allow saliva to enter the vacuum tubing leading to the vacuum pump.
For these reasons, it would be desirable to provide alternative and improved methods and apparatus for removing and collecting saliva in vacuum systems used with oral appliances and other devices. The methods and devices should be effective in cases of even the most excessive bubbling and foaming as well as in cases where the reservoir may be completely inverted. Such methods and systems should be simple and inexpensive to implement. At least some of these objectives will be met by the inventions described hereinafter.
2. Description of the Background Art
U.S. Patent Publication No. 2012/0132216 has been described above. U.S. Ser. No. 13/023,763, the full disclosure of which is incorporated herein by reference, is another co-pending, commonly owned U.S. Patent Application, filed on Feb. 9, 2011, and describes an alternative saliva management system of oral appliances. Oral and external devices for treating sleep apnea and snoring are described in U.S. Patent Publication Nos. US2005/166929; US2005/166928; US2008/0188947; US2007/0277818; US2008/0216843; and US2008/0210244; and in U.S. Pat. Nos. 7,182,082; 7,073,506; 7,073,505; 6,955,172; 6,877,513; 6,494,209; 5,957,133; 5,465,734; 4,676,240; 4,304,227; 4,169,473; and 3,132,647.